A loopback test may include the routing of electronic signals, digital data streams, or flows of items back to a source of the electronic signals. In some cases, the electronic signals may be routed without intentional processing or modification. A loopback test may be used to test a transmission or a transportation infrastructure. When using a loopback test to test connection problems, a device may send a specific pattern of data on a port and may detect the reception of the specific pattern of data on the same port as the port used to send the specific pattern of data.